Appropriate communication is at the heart of successful, healthy social interactions in humans. Deficits in social communication are a hallmark of several mental disorders, including autism spectrum disorders. Such disorders are characterized by extreme individual variability in the motivation to communicate, and in the ability to engage in socially appropriate communication, yet very little research has been devoted to understanding the neural bases of these issues. Songbirds provide an ideal model system in which to study brain mechanisms regulating appropriate social communication. In our model species we find the brain to differentially regulate communication in a context in which song is directed towards a female (goal-directed) versus song observed in large social groups (group-motivated). In past studies we find that some individuals communicate at high levels and others not at all. Associated with individual differences in communication are differences in activity within brain regions involved in motivation and reward. We have been able to motivate birds to communicate through pharmacological manipulations of dopamine receptors, suggesting dopamine as a candidate neurotransmitter system involved in stimulating communication in individuals that are not highly motivated to communicate. The experiments proposed here test the hypothesis that individual differences in context-appropriate communication are dependent upon dopamine activity within neural systems involved in motivation and reward. To test this hypothesis we will examine the effects of site-specific dopamine lesions (Aim 1) and site-specific dopamine receptor subtype manipulations (Aim 2) on communication within goal- directed and socially-motivated contexts in low- and high-communicating individuals. Neural circuits influenced by these manipulations will be examined after behavioral testing through examinations of markers of neuronal activity and other neurochemical markers. Comparisons will then be made of multiple dopaminergic markers in low- and high-communicators in both contexts to identify differences in the brain associated with natural individual variation in context-appropriate communication (Aim 3). The proposed research will identify manipulations that stimulate context-appropriate social interactions, which can be used in the design of clinical interventions in humans with deficits in the motivation to communicate. The proposed studies span from neurons, to neural circuits, to complex social behavior, integrate what is known about motivation with studies on communication, examine the influence of environment and social context on individuals displaying natural variation in behavior, and will provide treatment ideas for individuals with psychiatric disease. Deficits in social communication are a hallmark of several mental disorders, including autism spectrum disorders. Such disorders are characterized by extreme individual variability in the motivation to communicate, and in the ability to engage in socially appropriate communication. The proposed research will identify manipulations that stimulate context-appropriate social interactions, which can be used in the design of clinical interventions in humans with deficits in the motivation to communicate. [unreadable] [unreadable] [unreadable]